string的属性小试

//关于使用string
#include <iostream>
#include "string"
using namespace std;
 
//定义 
void  StrDefine()
{
    string str;
    cout << str << str.empty() << endl;//STL中包含了函数名重载.
    
    string str1(5,'a');//赋值字符串5个a 
    cout << str1 <<"    "<<str1.empty()<<endl;//str.empty中空的值为1，非空为0 
    
    string str2("abcdefg");//直接赋值abcdefg 
    cout << str2 <<endl;
    
    string str3("abcdefg" , 3);//截取前3个字符串 
    cout << str3 <<endl;

    string str4(str2 , 3 , 2 );//在a3的位置开始截取2个长度 
    cout << str4 <<endl;
    
    string str5(str2);//拷贝构造
    cout << str5 <<endl;    
 } 
 
//属性
void StrPro(){
    string str;
    cout <<str.capacity()<<endl;
    string str1(5,'a');
    cout <<str1.capacity()<<endl;//求容量，VS初始个数是15+16，VC初始个数是31+32    
    string str2("abcdefg");
    cout <<str2.length()<<endl;    //求长度 
    string str3("abcdefg" , 3);
    cout << str3.size() <<endl;//求个数 
    string str4(str2 , 3 , 2 );
    str4.resize(7);//重设字符个数 
    cout << str4.size() <<endl;
    cout << str4.length()<<endl;
    string str5(str2);

}
int main()
{
    //StrDefine;
    StrPro();
    
    system ("pause");
    return 0;
 } 

 

转载于:https://www.cnblogs.com/666fengmo666/p/7647527.html